Regression for a Parametric Survival Model
USAGE: 
survreg(formula = formula(data), data = sys.parent(), subset,
        na.action, link = c("log"), dist = c("extreme",
        "logistic", "gaussian", "exponential", "rayleigh"),
        fixed = list(), control, model = F, x = F, y = T, ...)
REQUIRED ARGUMENTS:
formula:
a formula expression as for other regression models. The response is usually a survival object as returned by the Surv function. See the documentation for Surv, lm and formula for details.
OPTIONAL ARGUMENTS:
data:
a data frame in which to interpret the variables named in the formula, or the subset argument.
subset:
expression saying that only a subset of the rows of the data should be used in the fit.
na.action:
a missing-data filter function, applied to the model.frame, after any subset argument has been used. Default is options()$na.action.
link:
transformation to be used on the y variable.
dist:
assumed distribution for the transformed y variable.
fixed:
a list of fixed parameters, most often just the scale.
control:
a list of three parameters (maxiter, rel.tolerance and failure) returned by survreg.control. See survreg.control and the EXAMPLES section for details.
model:
a logical value, if TRUE then the model frame is included as component model in the object returned by the function.
x:
a logical value, if TRUE then the model matrix is returned as component x in the object returned by the function.
y:
a logical value, if TRUE then the response is returned as component y in the object returned by the function.
...:
all the optional arguments to lm, including singular.ok.
VALUE:
an object of class survreg is returned, which inherits from class glm. See survreg.object for details.
Computation:
This routine is not as robust against nearly singular X matrices as lm; the problem occurs when the covariance matrix is explicitly inverted using the solve function. This can sometimes be solved by subtracting the mean from all continuous covariates.
SEE ALSO:
formula , lm , solve , Surv , survreg.control , survreg.object .
EXAMPLES: 
# Fit an exponential model
survreg(Surv(futime, fustat) ~ ecog.ps + rx, data = ovarian,
        dist = 'extreme', link = 'log',
        fixed = list(scale = 1))


# Using survreg.control to supply the control argument
survreg(Surv(days, event) ~ voltage, data = capacitor,
        control = survreg.control(maxiter = 40))